SU637266A1 - Method of machining ceramic articles - Google Patents

Description

I

The invention relates to methods for processing parts from ceramics based on pyrolytic boron nitride and can be used in electronic engineering and other areas of the national economy.

Based on well-known methods, they are grinding processes, more rarely - diamond cutting, the final machining of parts with special technical requirements is carried out simultaneously on several planes with high speed grinding wheels G2 | .

The closest technical solution to this is the method of processing ceramic parts by fixing them and subsequent processing with a GeT cutting tool,

However, the face listed methods have a number of drawbacks that do not allow to obtain high quality parts for pyrolytic nitride selection. When grinding ceramics from pyrolytic under-

the boron tride is stratified by the base material in a direction parallel to the direction of the preferred orientation of the crystals, which coincides with the direction of deposition of the blanks. The second type of defect is a spall on sharp edges, with a total scrap rate of 30-80%, depending on the dimensions of the parts and the quality of the original blanks. The need to apply a coolant during grinding entails additional delamination of the material being processed to brining the wheels.

Similar results are obtained.

5 and in the processing of pyrolytic boron nitride with diamond cutters.

The purpose of the invention is to eliminate the splitting and splitting of parts from pyrolytic boron nitride, as well as obtaining details of a complex configuration.

To achieve this goal, processing is carried out with a carbide blade tool with front and rear corners .0

mi sharpening 35 and 15, respectively, which is moved in direction, parallel or perpendicular to the plane of delamination, at a tactile speed of 0.01 to 0, 2 mm / rev, a cutting speed of 12O-2OO m / min and a depth of cut of not more than 0.05 mm

The use of the sharp-edge blade tool of the proposed geometry, together with the above-mentioned modes, ensures the maximum reduction of cutting forces, dramatically increases the yield of usable parts. Due to the thermal conductivity of boron nitride, which increases tool life by reducing the temperature in the treatment area and preventing the thermomechanical destruction of the workpiece, processing can be carried out without the use of coolant.

This, in turn, increases the yield of parts by eliminating the proppant of the fluid on the material.

The increase in yield of products also contributes to the use of a radius at the apex of an angle of no more than 0.05 mm and adjusting the cutting surfaces of the tool to 10-11 grade of cleanliness.

PRI me R. Cutted plates of pyrolytic boron nitride with previously ground surfaces parallel to the main base surface are used as blanks. On blanks, the method of color flaw detection determines the direction of the plane of the predominant orientation of the crystals with respect to the base plane. The fastening of the 1 st blank billet into the mandrel is carried out individually, and depending on the defectiveness of the base surface, the angle of inclination of the mandrel is established with respect to the direction of movement of the cutting tool (for example, a cutting and threading machine).

Mechanical machining of parts was carried out with a hard-alloyed chisel with a grinding angle of 5 35 (front angle) and 15 (rear angle), R at the tip of the cutter 0, O5 mm.

First, the process allowance is removed in diameter by means of a grooving tool up to 1.5 mm wide, leaving a 0.2 mm clearance for final processing. Then, a 2/3 allowance of the plane is removed with a cutting cutter, maintaining the following treatment mode: a cutting depth of 0.07 mm, a feed speed of 0.03 mm / rev, and a cutting speed of 15 m / min.

The final machining of the part with the diameter cutter is performed at a cutting depth of 0.03 mm, a feed speed of 0.01 mm / rev, and a cutting speed of 200 m / min. After that, the part is re-secured by installing the machined plane with the plane, ensuring that the base surface is parallel to this plane, and is again machined with the cutting edge of the above-mentioned machining mode on the plane,

When checking parts by size, the presence of chips (visually) and the presence of delaminations (by means of color flaw detection), it was determined that there was no defect in the manufacture of parts by this method, the delamination by delamination was 26% and the yield of parts was 7 4%.

In addition, the use of cylindrical mills for machining planes, for machining elliptical surfaces of boring tools and cylindrical end mills with sharpening angles of the cutting tool corresponding to the values indicated above, makes it possible to manufacture parts of complex configuration, and in all cases the quality of parts required for use is ensured. them in special areas of technology.

Claims (1)

1. Khrulkov V.A. and are. Mechanical processing of loops of ceramics and sitallo.3. The first testimony of the USSR Iza-in Saratov University, 1975. No. 341655, cl. In 28 D) 1/00, 1970.